A fad diet is a popular diet that generally promises quick weight loss.2 They are generally very restrictive, often under 800 calories, and do not follow evidence-based healthy eating guidelines.2 They are also frequently suboptimal in many nutrients, such as dietary fibre, carbohydrates, vitamins, minerals, and protective phytochemicals.3 Fad diets, and the products they recommend, can also be dangerous to a person’s health as they may promote malnutrition, nutrient imbalances and weight cycling.2 People will often initially report losing weight, however, the restrictive nature of fad diets is not sustainable long-term and many people regain the lost weight, and often some extra weight, once they liberalize their diet. Weight cycling may actually be more detrimental to a person’s health than simply remaining overweight or obese.4
Healthcare providers can help their patients identify fad diets by looking for some of the following red flags.3
- Promises weight loss of more than two pounds (1 kg) per week.
- Does not provide support for long-term weight loss success.
- Restricts you to less than 800 calories a day.
- Is rigid and does not fit into your lifestyle or state of health.
- Cuts out major food categories (like gluten or carbohydrates) and stops you from enjoying your favourite foods.
- Forces you to buy the company’s foods or supplements rather than show you how to make better choices from a grocery store.
- Uses “counsellors” who are actually salespeople trying to make a commission from what they sell.
- Gives you nutrition advice that is based on testimonials rather than scientific evidence.
- Promotes unproven ways to lose weight such as starch blockers, fat burners and colonic cleanses.
- Does not encourage physical activity.
- Recommendations based on a single study.
- Recommendations based on studies that have not been peer-reviewed.
- Simplistic conclusions drawn from a complex study.
Diet Detoxes and Cleanses
Diet detoxes and cleanses claim to help improve intestinal health, promote weight loss and remove ‘toxins’ ingested through the food/drinks we consume and the air we breathe.5 There is little scientific evidence that detox diets and cleanses actually promote these results.5 Many diet detoxes and cleanses are extremely restrictive and are not based on scientific evidence. These are generally meant to be short-term programs; however, they are often nutritionally insufficient.
Key Documents/Best Practice Guidelines
- 2006 Canadian clinical practice guidelines on the management and prevention of obesity in adults and children
- Recommendations for growth monitoring, and prevention and management of overweight and obesity in children and youth in primary care
- Recommendations for prevention of weight gain and use of behavioural and pharmacologic interventions to manage overweight and obesity in adults in primary care